#include<bits/stdc++.h>
#define REP(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
typedef long long int ll;
int main()
{
  string S;
  int cnt=0;
  cin >> S;
  REP(i,S.size()){
    if(S[i] <= '9' && S[i] >= '0')
      cnt += S[i] - '0';
  }
  cout << cnt << endl;
  return 0;
}